Some mobile devices have features for determining a geographic location. For example, a mobile device can include a receiver for receiving signals from a global satellite system (e.g., global positioning system or GPS). The mobile device can determine a geographic location, including latitude and longitude, using the received GPS signals. In many places, GPS signals can be non-existent, weak, or subject to interference, such that it is not possible to accurately determine a location using the GPS functions of the mobile device. In addition, the mobile device may not be able to determine its location using other conventional technologies (e.g., dead reckoning). For example, a mobile device may have been turned off and have traveled a long distance while turned off (e.g., in an airplane). As a result, the mobile device may not have a starting point for dead reckoning. When the mobile device is turned back on again (e.g., when the mobile device leaves the airplane and enters an airport building), satellite signals may be unavailable. Lacking GPS signals and a starting location, the mobile device can use neither GPS functions nor dead reckoning to determine a location when in the airport building. Meanwhile, a user of the mobile device may wish to know where in the airport building the user is located. The user may wish to know the location as quickly as possible, using the mobile device.